When a program that is on the air in normal television broadcasting is being recorded, character information such as braking news is sometimes superimposed on the image of the program on the air. In such a case, basically, the user does not want to record the emergency news itself although wanting to record the program. That is, in many cases, the character information such as emergency news included in video streams is unnecessary when recorded streams are watched (that is, after a lapse of time) although it is significant when watched in real time. For users who want to watch video streams intensively, such character information is a hindrance to comfortable video watching.
Therefore, a technology has conventionally been proposed that deletes the character information added to programs on the air. As an example of such a technology, a technology has been proposed such that the broadcasting side inputs an interpolation signal separately from the original video signal in generating a video stream and the receiving side plays back only the video signal from the video stream when necessary (Patent Document 1).
Patent Document 1: Japanese Laid-Open Patent Publication No. H09-200684